walkman - 7:15 pm on May 4, 2011 (gmt 0)
They may be serving the ads, but no one is clicking on them.
Some are but no where near enough. FB needs to show it can make money for the IPO so they are showing 5 ads for each page. The thing is that they have a lot of data and as advertisers move there, ads can be more targeted. Remember that Google makes a lot more from clicks than Bing simply by having a better ad algo. That can be changed since FB is attracting many Googler$.
Definitely a threat for others and finally an opportunity for advertisers. Hopefully they release their adsense too in time. We need Bing, FB and Amazon to compete with Google. Payouts and especially support will be improved.